Are the Norms of Bayley Screening Test Appropriate for Persian Language Children?

Objective
We aimed to assess the distribution of the Bayley screening test by age, and compare developmental risk category distributions between Persian language children and reference norms.


Materials & Methods
A representative sample of 417 children, 1 to 42-months-old, by consecutive sampling from health -care centers were enrolled, during 2014 to 2015 in Tehran, Iran. The cognitive, language and motor development of children were evaluated using Bayley screening test. For determining cut-off point for the subtest scores, two cut-offs were determined for each age group, that classified children to the at risk, emerging, and competent categories. We estimated the agreement of the risk categories between the two samples using weighted kappa statistics.


Results
About 70%-80% of all tests operated to the participating children were classified as normal by both norms. Weighted kappa coefficients for the five subtests ranged from 0.56 to 0.89 suggesting moderate agreement between two classification norms. Expressive and receptive communication had the lowest kappa scores (0.56 and 0.59, respectively), and classification of gross motor revealed the highest level of agreement (0.89).


Conclusion
Developmental disabilities are common disorders that impose important functional limitations on the affected children. Identifying infants at risk for developmental disorders by screening is a main step to minimize complications. Dependence on reference-based norms for the Bayley screening test in Persian language children results in misclassification of risk category.


Introduction
Developmental disorders are common problems that impose important functional limitations on developmental aspect of the affected children. In a study on 6150 infants, aged 1-18 months in Iran, the percentage of developmental delay varied depending on the considered cut-off point were reported, whereas, in referenced cut-off, 3.7% of study population had motor delay, and based on the Iranian cut-off points; it increased to 6.5% (10).
The Bayley screening test has been applied as a standard tool in developmental evaluation of infant in general pediatric populations, and it is particularly valuable in screening high-risk infants for developmental delay (11)(12)(13). This test briefly assesses cognitive, language, and motor developmental aspect of 1-42 months old children.
The period of test administration is short and a wide range of health practitioners with limited training can operate it.
There are apprehensions about the use of a developmental assessment tool in other countries that the test was produced (14,15 (2). Health conditions such as low birth weight (LBW), preterm birth, perinatal infection, and birth defects increase the risk for developmental problems (3). In our background, asphyxia, LBW, preterm birth, and high-risk pregnancy have been shown to exert adverse effects on neurodevelopmental aspects (4)(5)(6).
In less developed countries, accessibility of adequate screening for developmental disorders is limited where costs on health are meaningfully lower than those in developed countries.
Developmental disorders have a more damaging effect on health consequences in developing countries. Therefore determining at-risk infant for developmental abnormalities by screening tests is the main concern in less developed countries (7).
The American Academy of Pediatrics recommends that pediatricians screen all infants and children for developmental problems during routine office visits (8). Developmental screening and early intervention maximizes a child's ongoing functional abilities and helps to earn critical functional skills. However, without appropriate screening scale and relying on a clinician's experience can be misleading in detection between normal and abnormal development (8,9).
Although it is necessary to evaluate appropriate growth and development in all children, there are only limited national data in the developing countries, because there are no locally developed psychometric tools, for detection of developmental delays and most extant findings were collected for this process (17,18). Although an adapted scale improves cultural suitability, it is also resourceintensive especially on language and cognition tests and does not permit comparability across countries.
The revision of existing assessment scales can reduce bias in test items of specific structures; there is a risk of deviation unless these adaptations are accompanied by local norms, because children in an environment can, on average, be better than other children owing to cultural differences in the education of children and access to elementary education (14,15).
In this study, in order to evaluate the neurodevelopmental progress in Persian language children, we adapted and developed new norms to the Bayley screening test, and the distribution of developmental risk categories was compared with the norms of Tehran and the United States.  The comparison of risk categories based on Tehran and US cut-off points represents by   This is a first step in assessing the usefulness of the

Acknowledgement
The authors thank the specialists, study coordinators, staff, and families, who made this research possible. We express full acknowledgment and appreciation for the financial support of the